1. Field of the Invention
The invention relates to an orthopedic aid with two parts which are movable relative to one another and with a locking device for locking the two parts in a predetermined relative position and for unlocking the parts in order to permit movement of the parts with respect to one another.
2. Background Description
Orthopedic aids of this kind are used in many applications intended to provide compensation for temporary or permanent weaknesses of the human body and to enable functions that it would otherwise not be possible to perform. This is achieved by the orthopedic aid providing a supporting function in which, in a defined position of the parts of the aid, these parts are locked with respect to one another, and the locked position of the two parts with respect to one another corresponds to a position of use in which the patient concerned requires the supporting function afforded by the orthopedic aid. A preferred application of an orthopedic aid of this kind is in its design as an orthotic joint, where, for example, the parts of the orthotic joint connected to one another by a hinge can be locked in an extended position, for example in order to permit the function of a limb in the extended and locked position of the orthotic joint. To get to a rest position, the locking device has to be unlocked. In known orthotic knee joints, this is done, for example, by means of a Bowden cable with which the locking device can be unlocked, so that the knee joint can be flexed, for example in order to allow the patient to get to the seated position. After the patient stands up, the orthotic knee joint has to move back into the extended, locked position. If the locked position is not reached and the patient fails to notice this, there is a considerable risk of an accident happening since, when a load is placed on the orthotic knee joint that is assumed to be locked, the latter may buckle, and the buckling cannot be controlled by the patient because of the weakness of the joint. As a result, the patient may suffer a fall. For this reason, the patient has to pay particular care to ensure that the orthopedic aid is in fact really locked, for example by waiting for a sound, which indicates that the locking device has engaged, before placing any load on the aid.